Table A25.
Summary of findings table for the association between road traffic noise exposure and the incidence of ischaemic heart disease: ecological studies.
| Question | Does Exposure to Road Traffic Noise Increase the Risk of IHD | |||
|---|---|---|---|---|
| People | Adult population (men and women) | |||
| Setting | Residential setting: people living in Kaunas (Lithuania) | |||
| Outcome | The incidence of IHD | |||
| Summary of findings | RR per 10 dB increase in road traffic noise level (LDEN) | 1.12 (95% CI: 0.85–1.48) per 10 dB | ||
| Number of participants (# studies) | 262,830 (1) | |||
| Number of cases | 418 | |||
| Rating | Adjustment to rating | |||
| Quality assessment | Starting rating | 1 ecological study | 1 (very low) # | |
| Factors decreasing confidence | Risk of bias | Serious a | Downgrading | |
| Inconsistency | Na b | No downgrading | ||
| Indirectness | None c | No downgrading | ||
| Imprecision | None d | No downgrading | ||
| Publication bias | NA e | Downgrading | ||
| Factors increasing confidence | Strength of association | NA f | No upgrading | |
| Exposure-response gradient | Evidence of non-significant exposure-response gradient f | No upgrading | ||
| Possible confounding | No conclusions can be drawn g | No upgrading | ||
| Overall judgement of quality of evidence | 0 (very low) h | |||
# Since only one ecological study was available, we started with a grading of “very low” (1); a Ecological studies worked with a purposeful sample; so randomization and response rate is not an issue. The study was not able to adjust for important confounders at individual level, and was unable to apply individual exposure estimates; b Only one study was evaluated, so inconsistency was not an issue; c The study assessed population, exposure and outcome of interest; d Although the 95% CI contained values above 1.25, we considered the results to be precise: the number of participants, as well as the number of cases were much larger than 200; e Due to the low number of available effect estimates, it was not possible to test for publication bias or small study bias. However, when combining this study with the other case-control and cohort studies that investigated the association between road traffic noise and the incidence of IHD, the number of estimates became large enough to test for publication bias. The funnel plot (Figure 5.6 of the complete review) was somewhat a-symmetric, but the Egger test provided only weak evidence for small-study effects; f There was evidence of a non-significant exposure-response gradient: We found a non-significant effect size of 1.12 per 10 dB across a noise range of 55–75 dB; g We were not able to draw any conclusions whether possible residual confounders or biases would reduce our effect estimate; h The overall judgement of the quality of the evidence was “very low”(0). Downgrading of the overall level of evidence, because only one study was available, made no sense.